Purification of Isosorbide via Ion Exchange Resin for High-Performance Bio-Based Polycarbonate

Isosorbide-based polycarbonate (PIC) shows promising applications in medical devices and food packaging, owing to its excellent thermal stability, biosafety, optical properties, and scratch resistance. However, trace impurities, especially formic acid in isosorbide (ISB), can significantly influence the performance of PIC. Crude ISB was purified via ion exchange resin. Furthermore, the chromatographic parameters and the adsorption kinetics of formic acid were investigated. The results show that adsorption of formic acid follows the pseudo-second-order kinetic model, suggesting that it is chemisorption. The performance of PIC synthesized from purified ISB has been improved significantly, exhibiting number-average molecular weight (M_n) of 53.9 kg/mol, elongation at break of 10.2%, and Young's modulus of 1.84 GPa, along with notably enhanced thermal and optical properties.